#!/bin/bash

einfo() {
	echo "$*" >&2
}

die() {
    echo "$*" >&2
    exit 1
}

#
# The caller is expected to override the CONTAINER environment
# variable with the container they wish to launch.
#
BASE="registry.gitlab.com/xen-project/xen"
case "_${CONTAINER}" in
    _centos7) CONTAINER="${BASE}/centos:7" ;;
    _centos72) CONTAINER="${BASE}/centos:7.2" ;;
    _trusty) CONTAINER="${BASE}/ubuntu:trusty" ;;
    _xenial) CONTAINER="${BASE}/ubuntu:xenial" ;;
    _jessie) CONTAINER="${BASE}/debian:jessie" ;;
    _stretch|_) CONTAINER="${BASE}/debian:stretch" ;;
esac

# Use this variable to control whehter root should be used
case "_${CONTAINER_UID0}" in
    _1)   userarg= ;;
    _0|_) userarg="-u $(id -u)" ;;
esac

# Save the commands for future use
cmd=$@

# If no command was specified, just drop us into a shell if we're interactive
[ $# -eq 0 ] && tty -s && cmd="/bin/bash"

# Are we in an interactive terminal?
tty -s && termint=t

#
# Fetch the latest version of the container in hub.docker.com,
# unless it's a newly created local copy.
#
if [[ "_${CONTAINER_NO_PULL}" != "_1" ]]; then
    einfo "*** Ensuring ${CONTAINER} is up to date"
    docker pull ${CONTAINER} > /dev/null ||     \
        die "Failed to update docker container"
fi

if hash greadlink > /dev/null 2>&1; then
    READLINK=greadlink
elif [[ $(uname -s) == "Darwin" ]]; then
    echo "Unable to forward SSH agent without coreutils installed"
    unset SSH_AUTH_SOCK
else
    READLINK=readlink
fi

# Ensure we've got what we need for SSH_AUTH_SOCK
if [[ -n ${SSH_AUTH_SOCK} ]]; then
	fullpath_sock=$(${READLINK} -f ${SSH_AUTH_SOCK} 2> /dev/null)
	if [ $? -ne 0 ]; then
        echo "Invalid SSH_AUTH_SOCK: ${SSH_AUTH_SOCK}"
        unset SSH_AUTH_SOCK
    else
        SSH_AUTH_DIR=$(dirname ${fullpath_sock})
        SSH_AUTH_NAME=$(basename ${fullpath_sock})
    fi
fi

# Figure out the base of what we want as our sources
# by using the top of the git repo
if [[ -z ${CONTAINER_PATH} ]]; then
    CONTAINER_PATH=$(git rev-parse --show-toplevel)
fi

# Kick off Docker
einfo "*** Launching container ..."
exec docker run \
    ${userarg} \
    ${SSH_AUTH_SOCK:+-e SSH_AUTH_SOCK="/tmp/ssh-agent/${SSH_AUTH_NAME}"} \
    -v "${CONTAINER_PATH}":/build:rw \
    -v "${HOME}/.ssh":/root/.ssh:ro \
    ${SSH_AUTH_DIR:+-v "${SSH_AUTH_DIR}":/tmp/ssh-agent} \
    ${XEN_CONFIG_EXPERT:+-e XEN_CONFIG_EXPERT=${XEN_CONFIG_EXPERT}} \
    ${CONTAINER_ARGS} \
    -${termint}i --rm -- \
    ${CONTAINER} \
    ${cmd}

